Most empirical evaluation of diagnostic systems of emotional disorders (e.g., DSM-IV) has occurred at the categorical/descriptive level (e.g., diagnostic reliability and comorbidity) or has examined categories in isolation of related disorders. These findings provide little information on the validity of our nosology and the validity of conceptual models of the etiology, nature, and course of emotional disorders. Expanding on our recent work, research in the next project phase will test hypotheses pertaining to structural models of anxiety and mood disorders and trait variables implicated in the etiology, comorbidity, expression, and course of these disorders. Over 1,750 patients will be assessed using the Anxiety Disorders Interview Schedule: Lifetime version and associated instruments of key features of anxiety and mood disorders and measures of core temperament and personality (e.g., negative affect, behavioral inhibition). Dimensional measures of DSM-IV disorder features and personality, collected cross-sectionally and longitudinally, will be submitted to structural equation modeling to test competing models of the latent structure of DSM-IV emotional disorders, trait personality constructs, and their interrelationships. These studies will provide the first large- scale comparative evaluations of models of trait vulnerability and the influence of such constructs on the course of emotional disorders. Further analyses will evaluate the generalizability of the DSM-IV structure and its relationships with higher-order personality dimensions across races, sexes, and ages. Longitudinal analyses will examine the covariation of disorder and personality constructs as a function of psychosocial treatment and across two-year follow-up. Collectively, findings will indicate: (a) the shared, and specific dimensions of anxiety and mood disorders; (b) the possible treatment resiliency of higher-order personality dimensions influencing the course of disorders; (c) important reconceptualizations of personality models of emotional disorders; (d) refinements to the diagnostic definitions of emotional disorders and their cross-cultural aspects in DSM-V. This work will enhance and complement biological approaches to these issues by suggesting a more valid and robust set of disorder and personality constructs on which to base investigations such as familial, genetic, and etiologic studies-these data will foster a fuller integration of biological and psychological approaches to the structure and pathogenesis of emotional disorders. Taxometric studies will be conducted on selected DSM-IV disorders and personality constructs to examine whether these phenomena operate on a continuum or as taxa.